Act I. Pauline's room.
The servants of Pauline prepare the room for the night (choir and scene: " Déja dans l'azur des cieux "). She confesses to her confidante Stratonice the confusion of a dream where her husband, the Armenian aristocrat Polyeucte, was baptised and at once struck to death by Jupiter. Polyeucte appears soon, shaken by a Christians' new sacrifice which will be offered the next day to the heathen gods (duet: " Quelle morne douleur"). Pauline is horrified to learn that her husband sympathizes with their cause. Polyeucte also announces to her, that the day of the sacrifice was moved to coincide with the visit of Severe, an imperial general, who comes to celebrate a recent victory. Pauline does not need a presentation. She tells her husband that Severe used to be in love with her and that, without the intervention of her father, she would be today his wife. A square with a triumphal arch. The imperial group and Félix's following, governor of Armenia and father of Pauline, arrive at the sound of a triumphal march and a choir. Severe recognizes quickly Félix and Pauline; they present him Polyeucte as the husband of Pauline. Still in love with Pauline, Severe is startled to learn that she is married (quartet with choir: " Je frémis "). The curtain falls on the resumption of the parade and choir.
Act II. A garden with a small temple to Vesta.
One hearsin the distance the sounds of the celebration. However, Severe cannot share in the festivities, because he suffers to know Pauline married to the other one (story and cavatina: " O dieux, o puissances célestes "). He moves aside when Pauline enters with her suite. She deposits an offering in Vesta's temple. Severe reveals his presence and reminds her of the times when they were together (duet: " Pauline!...Dieux! "). Pauline asks him to forget the past, because she now has duties to her husband; she asks him not to try to see her again. Pauline returns to the temple and Severe hides at the approach of Polyeucte and his friend Néarque. They speak in vague terms of the imminent conversion of Polyeucte to Christianity. A wild site in the moonlight. Sextus, young Roman patrician, sings a barcarolle in the distance, while a boat transporting young people and women appears on the river. A Christian old man, Siméon, regrets the decadence of the heathen and leads in a group of Christian brothers. After a long prayer, Néarque presents Polyeucte to the faithful assembly, whereas Severe shelters in his hiding place. Polyeucte is baptized during a long ceremony.
Act III. A room in Félix's palace.
The heathen high priest Albin reveals to Félix, Polyeucte and Severe, that he has been informed about theprogress of a Christians' night-meeting, and he swears that Jupiter will bring down on them his vengeance. Severe hesitates to express such a hatred for the Christians; he indicates that he was a witness to the meeting and, without revealing any names, that a person of a very important social rank was baptized. After the departure of Félix and Albin, Polyeucte thanks Severe for his generosity, but adds that he would be happy to die for his faith. Before his departure, Severe admits his surprise that Polyeucte can hold his faith before his love for Pauline (story and cantilena: " Quoi, c'est peu de perdre Pauline! "). The sacrifice of the Christians in the temple is imminent and Polyeucte announces to his friend Néarque that he intends to smash the heathen idols (duet: " Où pensez-vous aller? "). Néarque agrees to join him. A square. At one end, the temple of Jupiter. After a long sacred procession, which brings the Christian victims, and an entertainment of heathen ballet, Polyeucte runs in and declares that he is a Christian and throws curses against the false gods of Rome. Pauline tries, in vain, to prevent him from achieving his project of destruction of the idols. The assembled crowd shouts for vengeance.
Act IV. A prison.
Polyeucte thoughts turn only towards heaven and the emptiness of temporal life (stanzas: " Source délicieuse "). Pauline implores him to save himself, and to save their marriage, by giving up his conversion, but her husband is deaf to her pleas (duet: " Polyeucte! Il en est temps encore! "). He comforts and consols himself in the recitation of the main events of the life of Christ. Pauline declares that she is ready to die for Polyeucte. Polyeucte tries to convince his wife to embrace Christianity, so that they can be united after death. Severe appears suddenly and offers Polyeucte the means to escape (trio: "Sévère! Vous ici "). Pauline begs Polyeucte to seize this opportunity, but Polyeucte remains determined to face his fate. In vain, Félix offers him a last chance to live by asking him to honour the heathen gods.
Act V. A square. At one end, an arena.
The crowd demands the blood of the Christians. Polyeucte is brought in and intones a chant of Christian credo. Pauline runs to join him, declaring that she has embraced the Christian faith. Both sing the Credo when they are led towards their death in the arena.